1. Field of the Invention
The present invention relates to a photometric device for a camera that uses the primary image formed on the camera's viewfinder screen to form a secondary image on the photometric sensor with a photometric lens.
2. Description of the Related Art
With the type of camera described above, the photographer's desired exposure may not be always achieved, since, if the image forming position of the secondary image on the photometric sensor has deviated from the design position, the photometric range which the photographer verifies through the viewfinder does not align with the range that the photometric sensor actually measures. Because of this, in the photometric device for a camera disclosed in Japanese Utility Model laid-open Application No.4-104610, a photometric sensor is provided at the focal surface of the photometric lens and is moved within the focal surface with the rotation of a decentering pin to enable adjustment of the image forming position of the secondary image on the photometric sensor.
In the device disclosed in the above mentioned publication, with one full rotation of the decentering pin, the photometric sensor returns to its original position, and it is necessary to determine the ideal position for the photometric sensor while the decentering pin is turning. As a result, fine adjustment of the position is difficult and sufficient resolving power may not be obtained with a photometric sensor that divides its light receiving portion into a great many sections to perform photometry on the photographic field or when a photometric lens with high magnification is used. Also, with the above mentioned device, when the decentering pin is rotated, the direction in which the photometric sensor moves changes in correspondence to the change in the direction the decentering pin travels. Because of this, the photometric sensor cannot be moved in a given direction continuously, resulting in further difficulty in adjustment.